1. Field of the Invention
The present invention relates to a power unit including an internal combustion engine and a transmission for changing the speed of the output power of the internal combustion engine wherein the output power of the changed speed provides a driving force.
2. Description of Background Art
A power unit that includes an internal combustion engine and a transmission is known. See, for example, Japanese Patent Laid-Open No. 2009-236128.
In the power unit disclosed in Japanese Patent Laid-Open No. 2009-236128, a driving force output power shaft is frequently supported for rotation on a casing provided continuously to an end portion of an engine main body. Further, between the casing which supports the driving force output power shaft for rotation thereon and the driving force output power shaft, an oil seal for preventing leakage of oil from within the casing is interposed. Thus, the oil seal is protected.